GB2365298A

GB2365298A - Flicker reduction for interlaced displays

Info

Publication number: GB2365298A
Application number: GB0024469A
Authority: GB
Inventors: Yoshihito Iwanaga; Shizuka Matsuda
Original assignee: Namco Ltd
Current assignee: Namco Ltd
Priority date: 2000-07-19
Filing date: 2000-10-06
Publication date: 2002-02-13
Anticipated expiration: 2020-10-06
Also published as: ITMI20002389A1; DE10052481C2; CA2322250A1; FR2812159B1; GB0024469D0; FR2812159A1; GB2365298B; DE10052481A1; ES2172430A1; JP2002044486A

Abstract

An image generation method to reduce flicker on an interlaced display including the step of synthesising colour data of an objective line B and colour data of an adjacent line on a frame image at a predetermined ration to make a synthetic colour data, to generate a field image on the basis of the synthetic colour data. This reduces flicker by reducing the lightness difference between adjacent line. Synthesising of colour data may be achieved using pixel interpolation. Preferably first synthetic data B<SB>U</SB> is found using the line above the objective line A and second synthetic data B<SB>L</SB> is found using the line below the objective line C, a second processing step may then be included to synthesize the first and second synthesised data by executing a translucent synthesis process to generate a field image.

Description

2365298 COMPUTER PROGRAM, COMPUTER PROGRAM PRODUCT, IMAGE GENERATION

APPARATUS, COMPUTER SYSTEM AND IMAGE GENERATION METHOD FOR GENERATING IMAGE

BACKGROUND OF THE INVENTION

Field of the Invention The present invention relates to a computer program, ò computer program product, an image generation apparatus, ò computer system and an image generation method for generating an image and, more particularly, to a generation of a field image for an interlaced display.

Description of Related Art

A variety of interlaced display devices are known. Herein, according to an earlier development, a television as the principal among these display devices will be explained, as follows.

NTSC system that is one of some video systems of televisions, scans odd lines by the first 1/60 seconds (display of an odd field) and then even lines by the next 1/60 seconds (display of an even field), thereby completes displaying one frame image. That is, one frame image is composed of two field images. Therefore, the bigger a lightness difference between each odd line image in the odd field and each adjacent even line image thereof in the even field, respectively, is, the more flicker is caused on the whole frame.

For example, when displaying a white cross line having one pixel wide, there may be a case that a white line exists on an odd line in the odd field and no white line exists on a neighboring even field of the odd line in the even field. In this case, because the white line flickers every 1/60 seconds, it is very hard to watch the frame.

A more specific example will be explained with reference to figures as follows. According to an image shown in each figure, the size of pixel on the image is enlarged and simplified to be simple and clear.

In FIG. 2, a frame image is shown wherein Chinese character "bi" with a white color is displayed against the black background. FIG. 21A shows the image of the odd field and FIG. 21B shows 'the image of the even field, to display the frame image as shown in FIG. 2. Chinese character "bi" is displayed by displaying the odd field image and the even field image continuously. In case that the lightness difference between the odd line and the neighboring even line thereof is big, the flicker is caused

2 on the frame image. FIG. 22 shows a lightness difference between the odd line and the neighboring even line thereof on the frame image as shown in FIG. 2. In FIG. 22, portions wherein the color changes from a white color to a black color or from a black color to a white color between the odd line and the neighboring even line are shown by a gray color. At the gray color portion flicker is caused.

The flicker as described above is caused on a still image of one Chinese character. Accordingly, the flicker can be caused very often and on all frames on the interlaced display device, and the flicker is caused practically. Further, although the explanation as described above is about the still image, the flicker is caused in a moving image as well as the still image.

on the other hand, as a device for generating or outputting images displayed on an interlaced display device, a video device, a personal computer, a home game device and so on are known.

However, such this type of device incorporates the hardware to reduce the above-described flicker and hence may be caused increasing a number of elements thereof and a cost thereof, and breaking down.

Additionally, according to the personal computer and 3 the home game device for generating images to be displayed as occasion demands, if it is possible to reduce flicker by controlling images to be generated by software, it is unnecessary to change some elements of each device so that it is convenient and useful extremely.

However, in order to reduce flicker by the software, a processing time becomes very serious problem. That is, in case of NTSC system, it is necessary to generate a field image within 1/60 second. Therefore, it is necessary to generate the field image in addition to generate an image as an original function, at 1/60 second. Accordingly, it is demanded that software comprises more advanced algorithm and design so that the software can generate a field image at a shorter time.

SUMMARY OF THE INVENTION

The present invention was developed in view of the above-described problems.

An object of the present invention is to reduce flicker on an interlaced display device by software processing.

In accordance with one aspect of the present 4 invention, a computer program comprises program code means for performing the step of: synthesizing color data of an odd line and color data of an even line on a frame at a predetermined'ratio to generate a field image for an interlaced display.

One frame image may be composed of two field images. For example, in case of NTSC system, each of two field images of the frame image is refreshed alternately every 1/60 seconds, that is, time interval to generate each field image.

Further, the size of the frame image is not limited to the size of the screen of the interlaced display to display the field images generated on the basis of the frame image. For example, the size of the frame image on NYSC system is different 'from the size of the frame image on PAL system regardless of the size of the screen to display the field images generated on the basis of each frame image. When the vertical length of the frame image is different from that of the screen, the upper and lower portions of the frame image may not be processed to generate each field image by the computer program of the present invention.

According to the computer program as described above, the field image is generated by synthesizing the odd line and the even line on the frame image so that it is possible to lighten the lightness difference between the odd line and the even line on the screen of the display device and it is possible to reduce flicker effectively. Further, means for reducing flicker is achievable by software as the computer program of the present invention. Consequently, in order to reduce flicker, for example, it is not necessary to incorporate an exclusive field image generation device in a personal computer or a game device and it is possible to use a processor provided beforehand with the personal computer and the game device itself.

The predetermined ratio for synthesizing each color data may be changed. That is, for example, when the field image to be generated is an image of an odd field, the color data ratio of the odd line against the even line is bigger, and when the field image is an image of an even field, the color data ratio of the even line is bigger. The ratio of synthesizing each color data may be changed. Further, in order to process simply and rapidly when synthesizing each color data, each color data may be synthesized at an equal ratio. Specifically, when synthesizing two data by using a bit shift operation and an additional operation, it is possible to process the data simply and rapidly by software.

6 The following description can be applied to the following computer program of the present invention like this computer program. The data quantity of the field image is half one of the frame image. That is, the field image has a half lengthwise size of one of the frame image so that the data quantity of the field image is a half quantity of the f rame image. As a result, the capacity of display memory to be used to display the field image on the display device has half one to be used to store the color data of the frame image, because the capacity is enough to store the color data of the filed image.

In accordance with another aspect of the present invention, a computer program comprises program code means for performing the step of: synthesizing color data of an objective line and color data of an adjacent line thereof on a frame image at a predetermined ratio to make a synthetic color data, to generate a field image for an interlaced display on a basis of the synthetic color data.

The following description can be applied to the following computer program of the present invention like this computer program. When. the field image to be generated is an image of an odd field the objective line is an odd line on the frame image, while when the field image to be generated is an image of an even field the objective

7 line is an even line on the frame image.

According to the computer program as described above, the color data of the objective line and one of the adjacent line thereof are synthesized so that, for example when the objective line is composed of one line, it is possible to generate a filed image reduced flicker easily by executing the operation for synthesizing each color data continuously with changing the objective line.

Further, the color data of the objective line and one of the adjacent line 'thereof are synthesized so that it is possible to generate an image in consideration of the adjacent line of the objective line.

Preferably, a computer program further comprises program code means for performing the steps of: synthesizing color data of the objective line and color data of an upper adjacent line thereof as the adjacent line on the frame image at a first predetermined ratio to make a first synthetic color data; synthesizing color data of the objective line and color data of a lower adjacent line thereof as the adjacent line on the frame image at a second predetermined ratio to make a second synthetic color data; and synthesizing the first synthetic color data and the second synthetic color data at a third predetermined ratio to make a synthetic color data, to generate a field image

8 for an interlaced display on a basis of the synthetic color data.

The upper and lower adjacent lines mean lines that are right above and below the objective line, respectively. The first and second synthetic color data mean color data as results of synthesizing color data of the objective line and color data of the upper and lower adjacent lines, respectively. Further, the first, second, and third predetermined ratios are determined individually so that they may be different from each other or at least two of them may be the same as each other.

According to the computer program as described above, it is possible to consider the upper and lower adjacent lines of the objective line. Further, the objective line is synthesized each of the upper and lower adjacent lines at each step, so that it is possible to process easily and rapidly. That is, as described above, it is possible to carry on the synthesis processing of two color data simply and rapidly so that the processing of the present invention becomes a combination of simple operations.

Accordingly, it is possible to realize a fast operation according to H/W composition of each device, for example, a processor which realizes a pipeline processing (practically, almost every processor can carry on the 9 pipeline processing) or comprises an exclusive circuit for synthesizing two image data (for example, BiLinear circuit), for carrying on the computer program of the present invention. As a result, it is possible to reduce a time for generating a field image.

In accordance with a further aspect of the present invention, a computer program comprises program code means for performing: a first processing step of synthesizing color data of an objective line and color data of an upper adjacent line thereof on a frame image at an equal ratio by executing a predetermined pixel. interpolation processing to make a first synthetic color data (for example, steps S1 to S8 as shown in FIG. 15; one of syntheses at Level 1 in FIG. 1B); and a second processing step of synthesizing color data of the objective line and color data of a lower adjacent line thereof on the frame image at an equal ratio by executing the predetermined pixel interpolation processing to make a second synthetic color data, and synthesizing the first synthetic color data and the second synthetic color data by executing a translucent synthesis processing (for example, Alpha-Blending) to generate a field image for an interlaced display (for example, steps S9 to S15 as shown in FIG. 15; the other of syntheses at Level 1 and the synthesis at Level 2 in FIG. 1B).

The predetermined pixel interpolation processing comprises Bi-Linear Filtering processing, Tri-Linear Filtering processing and so on, which are earlier developments. Executing the predetermined pixel interpolation processing means that, for example, the apparatus comprising the circuit as H/W for executing the predetermined pixel interpolation processing uses the circuit and the apparatus comprising the processing process as S/W (for example, a subroutine) uses the processing process.

According to the computer program as described above, it is possible to consider the.upper and lower adjacent lines of the objective line. Further, the objective line is synthesized at two processing steps and the objective line is synthesized from each of the upper and lower adjacent lines at each step, so that it is possible to process the objective line easily and rapidly.

Further, when the computer program of the present invention comprises the pixel interpolation processing and the translucent synthesis processing which are earlier developments, to synthesize each color data, it is possible to obtain the further effect of the present computer program embodied on a device as a circuit. That is, it is possible to shorten a generation time of the field image.

Further, one memory capacity is enough to store data of the field image. That is, the color data as the result of synthesis at the first processing step is synthesized one as the result of synthesis at the second processing step so that it is unnecessary to store the results at the first processing step and the second processing step, individually.

Preferably, a computer program further comprises program code means for performing the steps of.: executing Bi-Linear Filtering processing of sampling at four points as the predetermined pixel interpolation processing; and synthesizing color data of the objective line and color data of upper and lower adjacent lines thereof by executing Bi-Linear Filtering processing continuously after shifting positions of sampling by. a half pixel horizontally at the first and second processing steps respectively.

Bi-Linear Filtering processing is used on an image generation apparatus generally so that there are many cases that the image generation apparatus comprises Bi-Linear Filtering processing as a circuit. In such this case, as described above, the present invention is effective specially.

Further, although it is general to sample at four points as Bi-Linear Filtering processing, when carrying on Bi-Linear Filtering processing of sampling at four points 12 as it is, the color data of pixels horizontally is mixed. Therefore, the present processing is carried on after shifting the sampling position by a half pixel horizontally, thereby the sampling dose not cause mixing the color data of pixels horizontally.

Further, by shifting the sampling position by a half pixel horizontally, the case occurs that when the left or right end pixel on the objective line is synthesized the objective pixels of process by Bi-Linear Filtering processing do not exist.

Accordingly, preferably, a computer program further comprises program code means for performing the step of: synthesizing color data of a left or right end pixel on the objective line and color data of left or right end pixels of upper and lower adjacent lines thereof by executing BiLinear Filtering processing convolutedly, respectively.

Preferably, the predetermined ratio or at least one of the first, second, and third predetermined ratios is equal according to a number of objective lines of synthesis on the frame image.

According to the computer program as described above, it is possible to synthesize the image data without considering the ratio. Consequently, it is possible to realize the fast processing.

13 Preferably, a computer program further comprises program code means for performing the step of: synthesizing each color data per processing unit as a rectangular pixel group of a pixel number as a result of dividing a number of lengthwise pixels and a number of crosswise pixels on the frame image by a predetermined integral number respectively.

According to the computer program as described above, it is possible to synthesize the color data per processing unit corresponding to H/W composition such as a cashing or a paging. Consequently, it is possible to shorten the processing time for generating the field image.

Preferably, a computer program further comprises program code means for performing the step of: executing a translucent synthesis processing (for example, AlphaBlending synthesis) as synthesizing each color data.

According to the computer program as described above, for example, when the image data (color data) stored on the memory, of one field image and another image data (color data) not stored on the memory, of another image are synthesized, the capacity of the memory to store the image data of one field image is enough to synthesize the image data and another image data. That is, the necessary memory capacity for synthesizing each field image is one capable of storing one field image data. Consequently, it is

14 possible to carry on the computer program of the present invention on an apparatus limited a capacity of memory thereof.

Preferably, a computer program further comprises program code means for performing the step of: executing a predetermined pixel interpolation processing (for example, Bi-Linear Filtering processing) as synthesizing each color data.

According to the computer program as described above, there are a lot of cases that an image generation apparatus comprises the pixel interpolation processing as an existing function so that it is possible to generate the field image at a higher speed by the pixel interpolation processing.

Preferably, a computer program further comprises program code means for performing the step of: generating the field image as an image compressed the frame image in a lengthwise direction.

To compress in the lengthwise direction means to reduce the quantity of lengthwise image data and to reduce the size of lengthwise data of the frame image by synthesizing the color data so as to be described above.

Preferably,.the frame image comprises a size of a screen of the interlace display to display the field image or a bigger size than the screen.

Accordingly, it is not limited that the frame image comprises the substantially same size as the interlaced display to display the field image. For example, the frame image may be a long sideways image such a film.

Preferably, a computer program further comprises program code means for performing the steps of: not synthesizing color data of an upper or lower end line and color data of another line on the frame image; or synthesizing color data of the upper or lower end line on the frame image convolutedly (that is, using the upper or lower end line continuously).

Accordingly, when synthesizing two lines, it is possible to prevent from being inconsistent with the processing such that the objective line of synthesizing the upper or lower end line on the frame image does not exist.

Preferably, a computer program further comprises program code means for performing the step of: correcting color data of the field image brighter.

Accordingly, it is possible to brighter correct color data of the field image that has become dark necessarily by synthesizing each color data. Consequently, it is possible to hold the lightness of color data of the field image to the same extent as one of the original image

16 thereof.

Preferably, a computer program further comprises program code means for performing the step of: changing a level for correcting a lightness of color data of the field image.

Accordingly, for example, on a set up window or the like, it is possible to easily change the desired level for correcting the lightness. Further, as a method for realizing the correct of lightness specifically, for example, a method for multiply RGB values as color data by predetermined coefficients respectively can be provided.

However, the case can occur that an overflow on color data is caused by RGB values.

Accordingly, preferably, a computer program further comprises program code means for performing the steps of: multiplying color data of the field image by a predetermined coefficient to correct the lightness thereof; and correcting the lightness of color data of the field image after synthesizing color data of lines on the frame image when at least one of color data of the frame image exceeds a predetermined threshold value.

Consequently, the threshold value is determined in consideration of the color data and the coefficient, thereby it is possible to prevent from occurring such 17 problem as an overflow and a round caused by multiplying the color data by the predetermined coefficient.

Preferably, the objective line of synthesis is different according as whether generating an odd field image or an even field image.

Accordingly, for example, when generating the odd field the odd line and the lower adjacent line thereof on the frame image are synthesized, while when generating the even field the even line and the lower adjacent line thereof on the frame image is synthesized (if the even line and the upper adjacent line thereof are synthesized to generate the even field, the result of synthesis from the even line and the upper adjacent line thereof becomes the same as one of synthesis from the odd line and the lower adjacent line thereof). Consequently, it is possible to provide the resolving power in the vertical direction, as well as one of the original image.

More particularly, if thinking that the resolving power in the vertical direction comes down when the image of odd field is the same as one of even field on a still picture (a frame image),'it is possible to be understood the above description.

Preferably, the frame image is composed of full screen image data of the interlaced display per time to 18 display each field image.

Herein, per time to display each field image means every time interval to display each field image. For example, in case of NTSC system, it means every 1/60 seconds to display each field image. The term has the same mean in the whole present. specification.

Accordingly, the frame image is different every field image, individually. Consequently, it is effective to apply the computer program of the present invention to a display device having a low fresh ratio or a display device having a short afterglow wherein flicker is caused more strongly.

Preferably, a computer program further comprises program code means for performing the step of: changing ONIOFF of generation of the filed image.

Accordingly, for example, it is possible for a user to change ON/OFF of generation of the field image voluntarily on a set up window, or It is possible to change ONIOFF automatically according to each frame image (as the internal processing).

In accordance with a further aspect of the present invention, a computer program embodied on a storage medium comprises program code means for performing all the steps of any one described above when said computer program is 19 run on a computer.

In accordance with a further aspect of the present invention, a computer program embodied on a transmission medium comprises program code means for performing all the steps of any one described above when said computer program is runon a computer.

In accordance with a further aspect of the present invention, a computer program embodied in a carrier wave comprises program code means for performing all the steps of any one described above when said computer program is run on a computer.

Further, when the computer program as described above, for generating the image can be carried on by H/W capable to generate the image, it is possible to provide an effect of the present invention the most effectively.

That is, preferably, a computer program further comprises program code means, when said computer program is run on a home game device as the computer, the program code means performing the steps of: executing a predetermined game; and generating a game image of the predetermined game, composed of a field image reduced flicker.

Herein, the computer comprises not only one used generally such as a personal computer or the like but also any device incorporated a computer. Therefore, the computer comprises a home game device.

Preferably, a computer program further comprises program code means for performing the step of: changing ONIOFF of generation of the game image composed of the field image reduced flicker, according to a progress of the predetermined game.

Accordingly, for example, it is possible to change the generation of the field image reduced flicker to OFF at the game stage wherein the whole game image is dark.

Herein, the progress of the game means to advance the game according to the change of game stage (for example, the game stage to fight the boss character) or the growth of character.

In accordance with a further aspect of the present invention, a computer program product comprises program code means stored on a co mputer readable medium for performing all the steps of the computer program according to any one described above when said computer program product is run on a computer.

Preferably, a computer program product, further comprises program code means, when said computer program product is run on a home game device as the computer, the program code means performing the steps of: executing a predetermined game; and generating a game image of the predetermined game, composed of a field image reduced

21 f licker.

Preferably, a computer program product further comprises program code means for performing the step of: changing ONIOFF of generation of the game image composed of the field image reduced flicker, according to a progress of the predetermined game.

In accordance with a further aspect of the present invention, an image generation apparatus comprises program code means stored on a computer readable medium for performing all the steps of the computer program according to any one described above when said image generation apparatus is run on a computer.

Preferably, an image generation apparatus, further comprises program code means, when said image generation apparatus is run on a home game device as the computer, the program code means performing the steps of: executing a predetermined game program; and generating a game image of the predetermined game program, composed of a field image reduced flicker.

Accordingly, according to the image generation apparatus capable of carrying on said computer program, it is possible to provide an effect of the computer program of the present invention without reconstructing the image generation apparatus.

22 In accordance with a further aspect of the present invention, a computer system comprises a predetermined server and a predetermined terminal connected to each other through a predetermined electrical communication line, wherein the predetermined server comprises: program code means stored on a computer readable medium for performing all the steps of the computer program according to any one described above when said predetermined server is run on a computer; and means for sending said computer program to the predetermined terminal; and the predetermined terminal comprises: means for receiving said computer program from the predetermined server; and means for generating a field image reduced flicker by executing the computer program.

Accordingly, it is possible to download said computer program from the predetermined server to the predetermined terminal. Consequently, it ispossible for the predetermined terminal to carry on said computer program.

In accordance with a further aspect of the present invention, a computer system comprises a predetermined sever and a predetermined interlaced display device connected to each other through a predetermined electrical communication line, wherein the predetermined server comprises: program code means stored on a computer readable medium for performing all the steps of the computer program 23 according to any one described above when said predetermined server is run on a computer; means for generating a field image reduced flicker by executing said computer program; and means for sending the field image to the predetermined interlaced display device; and the predetermined interlaced display device comprises: means for receiving the field image from the predetermined server; and means for displaying the field image thereon.

Accordingly, it is possible for the predetermined server to send the image generated by said computer program to the predetermined interlaced display device.

In accordance with a further aspect of the present invention, an image generation method comprises all the steps of any one described above.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understand from the detailed description given hereinafter and the accompanying drawing which are given by way of illustration only, and thus are not intended as a definition of the limits of the present invention, and wherein:

FIG. 1A and FIG. 1B are views for explaining the 24 principle of the present invention; FIG. 2 is a view showing a frame image in which Chinese character bi- with a white color is shown against a black background;

FIG. 3A and FIG. 3B are views showing figure relations between field images and a frame image to which the present invention are applied on the basis of the frame image shown in FIG. 2;

FIG. 4A and FIG. 4B are views showing one example of an image to which the present invention is applied on the basis of the frame image shown in FIG. 2; FIG. 5A and FIG. 5B are views showing one example of an image to which the pre'sent invention is applied on the basis of the frame image shown in FIG. 2; FIG. 6A and FIG. 6B are views showing one example of an image to which the present invention is applied on the basis of the frame image shown in FIG. 2; FIG. 7A and FIG. 7B are views showing one example of an image to which the present invention is applied on the basis of the frame image shown in FIG. 2; FIG. 8A and FIG. 8B are views showing one example of an image to which the present invention is applied on the basis of the frame image shown in FIG. 2; FIG. 9 is a view showing one example of an image to which the present invention is applied on the basis of the frame image shown in FIG. 2; FIG. 10A and FIG. 10B are views for explaining a lightness difference before and after applying the present invention; FIG. 11 is a view showing one example of an image to which the present invention is applied on the basis of the frame image shown in FIG. 2; FIG. 12 is a view showing one example of a home game device according to the embodiment of the present invention; FIG. 13 is a diagram showing one example of a functional block of the home game device according to the embodiment of the present invention; FIG. 14A is a schematic view showing a memory structure of the frame image memory unit 282, and FIG. 14B is a schematic view showing a memory structure of the field image memory unit 284;

FIG. 15 is a flowchart of a field image generation processing;

FIG. 16 is a flowchart of a line synthesis processing; FIG. 17 is a diagram showing one example of a hardware structure capable of realizing the embodiment of the present invention; FIG. 18A and FIG. 18B are views showing a variety of embodiments to which the present invention is applied; FIG. 19A and FIG. 19B are views for explaining an 26 operation in Bi-Linear Filtering circuit of sampling at four points; FIG. 20A and FIG. 20B are views for explaining a variety of embodiments changing a processing unit; FIG. 21A and FIG. 21B are views showing the field image before applying the present invention to the frame image shown in FIG. 2;

FIG. 22 is a view for expressing flicker before applying the present invention to the frame image shown in FIG. 2.

PREFERRED EMBODIMENT OF THE INVENTION Hereinafter, an embodiment of the present invention will be explained in detail with reference to figures.

In the embodiment of the present invention, although the case will be explained that a display device is applied to TV in NTSC system and an image generation apparatus is applied to a home game device, as follows, it should also be understood that the present invention is not limited to the embodiment.

Further, in the embodiment of the present invention, although a frame image will be explained as an image of the whole screen of the display device, as follows, the frame 27 image may be an image having a bigger size than one of the whole screen of the display device.

Further, over the specification, a field image is one of a field in interlace scanning system, that is, one of either odd or even lines on the screen of the display device. Further, the field on odd lines is called an odd field and the field on even line is called an odd or even field. Each field image on the odd or even field is called an odd or even field image, respectively.

Further, the home game device in the embodiment can generate a frame image every 1/60 seconds like a home game device according to an earlier development.

Firstly, the principle of the present invention will be explained, as follows.

The image data on the frame image and the field image comprise RGB values per pixel. In order to express the image in 16777 thousand colors socalled full color, it is necessary that each of RGB values per pixel is 8 bit data, as shown in the following equation.

2"(R) x 2"(G) x 2"(B) = 16,777,216 It is possible for a general computer to average two numerical values simply. That is, it is possible to average two numerical values at less operation steps (there are many cases wherein the step is called a state at a 28 level of machine language) by combining a bit shift operation and an additional operation. Further, it is generally that the computer operates every 8 bits as a basic unit. Therefore, each of RGB values, having integer 8 bits is a preferable data type for a computer.

FIG. 1A is a view showing adjacent three lines A, B, and C on the frame image. Now, the case that the present invention is applied to an image of line B as one line of the field image will be considered.

FIG. 1B is a view showing an operating process according to the embodiment of the present invention.

In the embodiment of the present invention, an image is synthesized at two steps of Level 1 and Level 2.

Firstly, at Level 1, an image data of a line to be an object of synthesizing (an objective line) and one of a line to be right above the objective line (an upper line) are average to be synthesized, and the image data of the objective line and one of a line to be right below the objective line (an lower line) are average to be synthesized. In FIG. 1B, by synthesizing line B and line A, a synthetic line Bu is generated. Further, by synthesizing line B and line C, a synthetic line BL is generated.

In the processing at Level 1, the objective line and 29 the upper or lower adjacent line thereof are synthesized, and the upper or lower adjacent line not synthesized and an upper or lower line than the objective line by 2 lines is synthesized, respectively. Therefore, the lightness difference between the adjacent lines is lightened so that it is possible to reduce flicker enough only by the processing at Level 1.

According to an apparatus to which the present invention is applied, for reasons of a processing time, it may be finished generating a field image at the step of Level 1 and, more particularly, it may synthesize the objective line and either the upper or lower adjacent line thereof. However, in the embodiment of the present invention, the image data are synthesized at the more step.

That is, at Level 2, image data of two synthetic lines generated at Level 1 are further averaged each other to be synthesized. In FIG. 1B, the synthetic line Bu and the synthetic line BL are synthesized, thereby a synthetic line B' is generated. The synthetic line B' is actually displayed on the display device.

As described above, the objective line and the upper adjacent line thereof are synthesized and the objective line and the lower adjacent line thereof are synthesized, thereby it is possible to lighten the lightness differences between the objective line and the upper adjacent line and between the objective line and the lower adjacent line. Consequently, it is possible to reduce flicker effectively.

Further, according to the synthetic line B', after synthesizing the synthetic line Bu and the synthetic line BL, the 50% of image data (the color data) of the original line B is still existed (the 25% of line A and the 25% of line C are still existed). Consequently, it is possible to display the image having an original resolving power.

It is needless to say that the synthesis of lines means to average RGB values of each pixel on the line, respectively.

According to the operating process as described above, it is necessary to operate three times (two times at Level 1 and one time at Level 2) to synthesize on one objective line after all. However, any operation uses the same operation expression in the respect of "synthesis" (as follows, although each operation carries on the difference operation expression as the actual implement, by using BiLinear Filtering processing or AlphaBlending processing, they are the. same conceptually.. Further, the operations processes each of RGB values of each pixel on all lines of field image in the same way. Although it is limited that the operation result at Level 1 is used at Level 2, it is

31 possible to carry on each operation independently.

Therefore, it is possible for the processor capable of carrying on a parallel processing as a pipeline processing (almost every processor which needs to operate at a high speed such as a home game device can process at parallel) to operate at a high speed. Further, it is possible for an apparatus comprising a plurality of processors to operate at parallel easily.

Further, although a loop operation is carried on continuously at the actual implement, each data is independent on each loop operation so that it is possible to operate suitably to the parallel processing.

The lightness of the whole screen or the object as the display object may be changed by applying the present invention thereto, although it dependents on the image to displayed on the whole screen or the object. Specific example will be explained, as follows. Each RGB value is determined 'anyone value of 0 to 255 (28=256), thereby one color is determined. For example, RGB values of white color have R=255, G=255, and B=255, and RGB values of black color have R=O, G=O, and B=O. Accordingly, RGB values of average color between a black color and a white color have R=128, G=128, and B=128.

As shown in the numerical value, by applying the 32 present invention, the color of the object (more correctly, the color of the outline portion on the object) is mixed with one of the background thereof and so on. Therefore, the bright portion of the object becomes dark so that the whole image becomes darker than the lightness of the original image. Accordingly, when synthesizing colors, it is necessary to correct the lightness. However, RGB values are numerical values, and the bigger the RGB values are, the brighter the color having the RGB values is, so that it is possible to easily correct the lightness by multiplying the RGB values by more than 1 coefficient.

Secondly, an example of image to which the present invention is applied will be explained.

FIG. 2 is a view showing a frame image In which Chinese character "bi" with a white color is shown against a black background. The pixel of the image shown in each figure is enlarged to be simple and clear.

FIG. 3 is a view showing figure relationships between the field image and the frame image (FIGS. 4 to 9, and FIG. 11) to which the present invention is applied on the basis of the frame image shown in FIG. 2.

FIG. 4A and FIG. 5A show the result images of synthesis of Level 1 on the odd field of the frame image

33 shown in FIG. 2. FIG. 4A shows the image synthesized from the objective line and the upper adjacent line thereof, and FIG. SA shows the image synthesized from the objective line and the lower adjacent line thereof.

FIG. 4B and FIG. 5B show the result images of lightness correct of two images shown in FIG. 4A and FIG. SA, respectively. The coefficient of the lightness correct for multiplying RGB values is 1.07.

FIG. 6A and FIG. 7A show the result images of synthesis of Level 1 on the even field of the frame image shown in FIG. 2. FIG. 6A shows the image synthesized from the objective line and the upper adjacent line thereof, and FIG. 7A shows the image synthesized from the objective line and the lower adjacent line thereof.

FIG. 6B and FIG. 7B show the result images of lightness correct of two images shown in FIG. 6A and FIG. 7A, respectively.

FIG. 8A shows the result image synthesized at Level 2, on the basis of the images shown in FIG. 4B and FIG. 5B. FIG. 8B shows the result image synthesized at Level 2, on the basis of the images shown in FIG. 6B and FIG. 7B.

The image of odd field (FIG. 8A) and the image of even field (FIG. 8B), as the results of the image synthesis

34 at Level 2 are displayed on the display screen. FIG. 9 shows a frame image from two field images. As compared with the original image shown in FIG. 2, it is understood that the lightness difference between the adjacent lines is lightened.

on the field images not been processed according to the present invention, as shown in FIG. 21A and FIG. 21B, the ligh tness difference between adjacent lines is shown by color in FIG. 10A. On the field image processed according to the present invention, as shown in FIG. 8A and FIG. 8B, the lightness difference between adjacent lines is shown by color in FIG. 10B.

In FIG. 10A and FIG. 10B, the bigger the lightness difference between adjacent lines is, the nearer to a white color the image is, and the smaller the lightness difference is, the nearer to a black color the image is.

It will be understood that before applying the present processing to the image, the lightness difference is large and f licker is caused hard. Further, it - will be understood that by applying the present processing to the image, the lightness difference becomes extremely small and flicker is reduced effectively.

FIG. 11 shows the image after being processed at Level 1, that is, the image displayed the image of odd field as shown FIG. 4B and the image of even field as shown in FIG. 6B. As compared the image as shown in FIG. 11 with the original image as shown in FIG. 2, it will be understood that the lightness difference between the adjacent lines is lightened at Level 1.

FIG. 9 shows the image after being processed at Level 2. As compared the image as shown in FIG. 9 with the image as shown in FIG. 111, it will be understood that it is possible to generate an image having the same extent to the original resolving power by processing the image at both Level 1 and Level 2.

Further, applying the present invention will cause the following doubt. It is whether a different color from the original color is displayed, that is, for example, whether the purple color line is displayed when a red color line and a blue color line are neighboring to be synthesized.

However, the interval between the neighboring lines on the display screen is small extremely. Further, when displaying the red line and the adjacent blue line alternately on an interlaced display device, the purple color line is seen by afterimage phenomena. Accordingly, because a change of color on the display screen is not invisible to the naked eye, it is not doubtful.at all.

36 FIG. 12 shows one example of home game device according to the embodiment of the present invention.

In FIG. 12, with watching a game image displayed on the display 1200, a player controls game controllers 1202 and 1204, thereby he enjoys the game executed by the home game device main body 1210. In this case, the necessary data for playing the game such as the game program and so on, is stored on CD-ROM 1206, IC card 1208, a memory card 1212 or the like, as a data storage medium which is capable to take on and off the main body.

FIG. 13 is a diagram showing one example of functional block of a home game device as an image generation apparatus. The functional block comprises an operation control unit 10, a processing unit 20, a display unit 30, and a memory unit 40.

The operation control unit 10 is inputted an operation control data by a player, and the function thereof can be realized by a hardware comprising a lever, a button and so on. When pushing the button and so on, an operation control signal is outputted from the operation control unit 10 to the processing unit 20. The operating member corresponds to game controllers 1202 and 1204 and so on, as shown in FIG. 12.

37 The processing unit 20 comprises a game operation unit 22, an image generation unit 24, a field image generation unit 26, and an image data temporary memory unit 28. The image data temporary memory unit 28 comprises a functional block for memorizing data so that the image data temporary unit 28 belongs to the memory unit 40. However, because the image data temporary memory member 28 is related to the image generation unit 24 and the field image generation unit 26 strongly, it will be shown in the figure and explained that the image data temporary memory unit 28 belongs to the processing unit 20.

The function of the processing unit 20 is realized by hardware such as CPU (CISC type, RISC type), DSP, ASIC (gate array), a memory (ROM., RAM) or the like. The function of the image data temporary memory unit 28 is realized by hardware such as RAM, VRAM or the like.

The game operation unit 22 carries on a processing for arranging objects including characters in an object space (game space), a processing for controlling movements of characters on the side controlled by the computer, a processing for setting a virtual camera as a point of view in the game space, in the object space or the like, on the basis of the operation control signal and a game program 42, an object data 44 and so on, memorized in the memory unit 40.

38 The image generation unit 24 carries on a processing for generating an image at a point of view of the virtual camera in the object space set by the game operation unit 22. Further, the image generated by the image generation unit 24 is a frame image every 1/60 seconds (that is, every field unit in NTSC system). Further, the frame image generated is stored in a frame image memory unit 282 of the image data temporary memory unit 28.

The image data temporary memory unit 28 comprises a frame image memory unit 282 and a field image memory unit 284. FIG. 14A is a view showing a schematic memory structure of the frame image memory unit 282. FIG. 14B is a view showing a schematic memory structure of the field image memory unit 284.

The frame image memory unit 282 memorizes a frame image as an image data of the whole screen of the display unit 30. The field image memory unit 284 memorizes a field image to be displayed on 'the display unit 30 every 1/60 seconds. The frame image memory unit 282 has a capacity of 24 (=8+8+ 8) bits every pixel to store RGB values each pixel. The field image memory unit 284 has a capacity of 24 (=8+8+8) bits every pixel to store RGB values each pixel. Therefore, the memory capacity to memory the field image is half of one to memory the frame image.

39 Alpha-Blending synthesis is a processing used by the image generation apparatus generally and used especially when translucent synthesi.zing from one image data and the other image data. It is possible to synthesize the image at the two steps in a less memory capacity and at a higher speed, by using the processing.

That is, f irstly, an image data of line Bu as a result of synthesis from line A and line B in FIG. 1B, is memorized in the field image memory unit 284. Secondly, an image data of line BL as a result of synthesis f rom line B and line C and the image data of line Bu memorized In the field image memory unit 284 are synthesized by AlphaBlending synthesis. Therefore, a space (memory) to temporary memorize the image data of line BL is unnecessary so that it is possible to generate the image data of line B' directly.

The field image generation unit 26 carries on a field image generation processing (with reference to FIG. 15) and a line synthesis processing (with reference to FIG. 16) according to a field image generation program 46 memorized in the memory unit 40. Thereby, the field image generation unit 26 generates a field image from the frame image memorized in the frame image unit 282. That is, the field image generation unit 26 synthesizes the image data at the two steps as described above. Further, the field image generation unit 26 realizes synthesizing at a high speed by using Alpha-Blending synthesis as one part of synthesis processing of the image data.

The field image is displayed on the display unit 30 after being stored in the field image memory unit 282.

FIG. 15 is a flowchart showing a field image generation processing following a processing algorism of the field image generation program 46. FIG. 16 is a flowchart showing a line synthesis processing following a processing algorism of the line synthesis program 462 as a subroutine of the field image generation program 46.

The field image generation program and the line synthesis program are carried on continuously every 1/60 seconds. Therefore, in FIG. 15 and FIG. 16, the processing for generating only one field image is shown.

Firstly, some constants used by the two programs will be explained, as follows. The constants comprises Y,in showing the minimum number of scanning lines on the display unit 30 and Ym, showing the maximum number of scanning lines on the display unit 30. Therefore, on the display unit 30, scanning lines from the Y,in to the Y,a, are existed. The frame image is composed of the images from the Y 41 scanning line to the Y... scanning line.

Secondly, the field image generation processing will be explained, as follows.

In FIG. 15, when starting the field image generation processing, the field image generation unit 26 substitutes "1" for the various f when the field image to be generated is an odd field, while the field image generation unit 26 substitutes "0" for the various f when the field image is an even field (step S1). In order to synthesize from the objective line and the upper adjacent line thereof by the line synthesis processing, the field image generation unit 26 substitutes "1" for the various D (step S2). Thereafter, the field image generation unit 26 stores the value of the constant Y in the various y (step S3).

The field image generation unit 26 stores a total value of double values of the various y and the value of the various f in the various Y (step S4) . Thereafter, the field image generation unit 26 carries on the line synthesis processing as a subroutine of this field image generation processing (step S5).

Although the line synthesis processing will be explained in detail, as follows, in a word about the function thereof, it is a processing for synthesizing from 42 a line having the value of the various Y (following, it will be called Y line) and an upper or lower adjacent line thereof.

The field image generation unit 26 substitutes the synthetic image data of Y line as the result of the line synthesis processing at the step S5 for a position corresponding to the line having the value of various y of the field image memory unit 282 (following, it will be called y line) (step S6). Thereafter, the field image generation unit 26 increments the value of various y by "1" (step S7), and carries on the processing from step S4 to step S7 continuously until the value of various y exceeds the half value of the constant Y,,, (step S8).

After the processing of step S8, the field image generation unit 26 substitutes "-1" for the various D in order to synthesize from the objective line and the lower adjacent line thereof by the line synthesis processing. Thereafter, the field image generation unit 26 stores the value of constant Y,j, in the various y (step S10).

The field image generation unit 26 adds the double values of various y to the value of the various f, further subtracts "1", and further stores the value in the various Y (step 11). The field image generation unit 26 carries on

43 the line synthesis processing (step 12).

As a result of the line synthesis processing at step S12, the field image generation unit 26 updates the image data of y line memorized in the field image memory unit 282 by Alpha-Blending synthesis from the synthetic image data of Y line synthesized at step S12 and the image data of y line memorized in the field image memory unit 282 (step S13).

The field image generation unit 26 increments the value of various y by "l" (step S14). The field image generation unit 26 carries on the processing from step S11 to step S14 continuously until the value of various y exceeds the half value of constant Y,a, (step S15). When the field image generation unit 26 judges that the value of various y exceeds the half value of constant Y,a,, the field image generation unit 26 finishes the field image generation processing.

Next, the line synthesis processing will be explained, as follows.

In FIG. 16, when starting the line synthesis processing, the field image generation unit 26 stores the image data of Y line memorized in the frame image memory unit 282 in the various (Rc, Gc, Bc) (step A1). When the

44 value of various D equals "1" (step A2), the field image generation unit 26 judges whether the total value of the value of various Y and the value of various D exceeds the constant Y (step A3).

When judging that the total value exceeds the constant Ym,, the field image generation unit 26 stores the image data of a line having the value of constant Ymax (following, the line will be called Y,aA in the various (R1, G1, B1) (step A4). When judging that total value does not exceed the constant Y,a,,the field image generation unit 26 stores the image data of a line having the total value of the value of various Y and the value of various D in the various (R1, G1, B1) (step AS).

At step A2, when the value of various D equals "-1", the field image generation unit 26 judges whether the total value of the value of various Y and the value of various D is less than the constant. Y,j, (step A6).

When judging that the total value is not less than the constant Y,j.,, the field image generation unit 26 stores the image data of a line having the total value of the value of various Y and the value of various D in the various (R1, G1, B1) (step AS). When judging that the total value is less than the constant Y,j,, the field image generation unit 26 stores the image data of a line having the value of constant Y,j, (following, it will be called

Y,in) in the various (R1, G1, B1) (step A7).

After the processing at step A4, A5, or A7, the field image generation unit 26 adds the various (Re, Ga, Bc) multiplied by the value of various y to the various (R1, G1, B1) multiplied by the value of various 6. And further, the field image generation unit 26 multiplies the value by the value of various c, and stores the result of multiplication in the various (R', G', B'), thereby finishes the line synthesis processing (step A8).

In the line synthesis processing, although it will be explained thatimage data (RGB values) of each line is stoked in the various collectively in order to be explained simply, the processing is carried on every pixel composing each line in the practical implement.

Further, in order to enable to change the ratio of synthesis, the line synthesis processing is expressed by using the various y and the various That is, f or example when synthesizing from the images at the average ratio, the various and the various 6 may store "0.5" therein. Further, in order to operate for synthesizing from the images at the average ratio at the high speed, the processing at step A8 may be processed by using the bitshif t operation and not using the various y and the various 46 Further, the various 8 indicates a coefficient for correcting the lightness. For example, in order to correct the lightness 10 percent brighter, the processing may be carried on with storing "1.1" in the various e.

Although the line synthesis program 462 is a subroutine of the field image generation program 46, it is needles to say that it may be an independent program.

As shown in FIG. 15, FIG. 16, and the abovedescribed explanation clearly, the present field image generation processing includes many loops (for example, the operation from step S4 to step S8). However, the data does not depend each other at all between each operation loops so that it is possible to process the data at parallel at the same time. Although the operation every pixel becomes frequent extremely, as described above, the operation every pixel is independent separately so that it is possible to operate at a high speed..

The memory unit 40 memorizes the game program 42 as a program and the field image generation program 46 to be read out and processed by the field image generation member 26. Although the line synthesis program 462 is included in the field image generation program 46, as a subroutine

47 thereof as shown in figures, the line synthesis program 462 may be separated from the field image generation program 46.

Further, the memory unit 40 memorizes the object data 44 as objects comprising characters and data related to the light source, the virtual camera and so on. It is possible for the memory unit 40 to realize the function thereof by hardware such as CD-ROM, a game cassette, IC card, MO, FD, DVD, a hard disc, a memory and so on. As described above, the processing unit 20 carries on various processing on the basis of the program and data read out from the memory unit 40.

An example of composition of hardware capable of realizing the embodiment of the present invention will be explained with reference to FIG. 17. An apparatus as shown in FIG. 17, comprises CPU 1000, ROM 1002, RAM 1004, a data storage medium 1006, a sound generation IC 1008, an image generation IC 1010, and I/0 ports 1012 and 1014, which are connected to each other through a system bus 1016 so that which can input data to and output data from each other. The image generation IC 1010 is connected with a display device 1018, the sound generation IC 1008 is connected with a speaker 1020, the I/0 port 1012 is connected with a control device 1022, and I/0 port 1014 is connected with a communication device 1024.

48 The data storage medium 1006 is mainly memorized a program, an image data for displaying a display object, a sound data, play data and so on therein.

For example, according to a home game device, CD-ROM, a game cassette, WD and so on are used as the data storage medium to store the game program and so on, and a memory card and so on are used as the data storage medium to store the play data. Further, according to a game device for business use, a memory as a ROM and so one and a hard disc, are used as the data storage medium. In this case, ROM 1002 functions as the data storage medium 1006.

The control device 1022 corresponds to a game controller, a controlling panel and so on, to input the result of judgment by a player according to a progress of game to the apparatus body. The control device 1022 corresponds to the game controllers 1201 to 1204 as shown in FIG. 12.

CPU 1000 controls the whole apparatus and processes each type of data, according to a program stored in the data storage medium 1006, a system program (an initial data of the whole apparatus, and so on) stored in ROM 1002, a signal inputted from the control device 1022 and so on. RAM 1004 is a memory member to be used as an operation area of the CPU 1000 and so on, and corresponds to the image 49 data temporary memory unit 28 as shown in FIG. 13. Further, RAM 1004 stores the predetermined data of the data storage medium 1006 and ROM 1002, the operation result by CPU 1000 or the like.

Such this type of apparatus further comprises the sound generation IC 1008.and the image generation IC 1010 to suitably output a game sound and a game image, respectively.

The sound generation IC 1008 is an integrated circuit for generating a game sound such as a sound effect, a back ground music or the like on the basis of the data memorized in the data storage medium 10006 or ROM 1002. The game sound generated by the sound generation IC 1008 is outputted from the speaker 1020.

The image generation IC 1010 is an integrated circuit for generating a pixel data to be displayed on the display device 1018 on the basis of the image data sent from RAM 1004, ROM 1002, the data storage medium 1006 or the like. Although the functional block corresponding the image generation IC corresponds to the image generation unit 24 and the field image generation unit 26 as shown in FIG. 13, it is possible to realize the function of two functional block by CPU 1000.

The display device 1018 may be realized by CRT, LCD, TV, a plasma display, a projector or the like.

The communication device 1024 communicates various data to be used in an inside of the game device between the game device and the outside thereof. The communication device 1024 is used to send/receive the predetermined data according to the game program to/from another game device connected or to send/receive the data of game program or the like through the communication line.

Various types of processes such as the game, the field image generation processing, the line synthesis processing and so on, are realized by the data storage medium 1006 to store the program and so on for carrying on the processes, CPU 1000 to operate according to the program, the image generation IC 1010, the sound generation IC 1008 and so on.

FIG. 18A shows an example of the case of applying the present invention to a game device for business use. A player enjoys a game by controlling a lever 1102, a button 1104 and so on with watching a game image displayed on a display 1100. On a system board (a circuit board) 1106 incorporated in the game device for business use, various processors, various memories and so on, is equipped. Further, data (program and data) for carrying on each member of the present invention, such as the field image

51 generation processing and. so on is stored in a memory 1108 as a data storage medium on the system board 1106 (following, the data will be called a storage data).

FIG. 18B shows an example of the case of applying the present embodiment to a system comprising a host apparatus 1300 and terminals 1304-1 to 1304n connected to the host apparatus 1300 through a network 1302 (the network may be a small area network as LAN or a wide area network as Internet and have a circuit form of wireless or wired). In this case, the above-described storage data is stored in a data storage medium 1306 such as a magnetic disc device, a magnetic tape device, a memory or the like capable to be controlled by the host apparatus 1300. In the case that the terminals 1304-1 to 1304-n can generate the game image and game sound at stand-alone, the host apparatus 1300 sends the above-described storage data which is the game program for generating the game image and game sound, to the terminals 1304-1 to 1304-n.

The host apparatus 1300 may be composed to generate a game image and a game sound by carrying on the field image generation processing and so on, on the basis of the abovedescribed storage data stored in the data storage medium 1306, and to let the terminals 1304-1 to 1304-n display the game image on, the terminals by sending the game

52 image and the game sound to the terminals. Further, in this case, although the host apparatus 1300 generates the field image (game image) and sends it to the terminals 1304-1 to 1304-n without being under the control of the terminals, the host apparatus 1300 may generate and send the field image (game image) according to the input from each of terminals 1303-1 to 1304-n. When sending the field image (game image) from the host apparatus 1300 to each terminal, it is preferable to use a line having a high speed as ADSL.

In the case of composition shown in FIG. 18B, the host apparatus (server) and the terminals may share in various members of the present invention to carry on them individually. Further, the storage data for carrying on each member of the present invention may be distributed to the host apparatus (server) and the terminals to storage them individually.

The terminal connected to the network may be a home game device as shown in FIG. 12 or a game device for business use. And further, the structure as shown in FIG. 18B may be realized by applying a game device for business use as the host apparatus and some home game devices as the terminals.

53 Although the present invention has been explained according to the above- described embodiment, it should also be understood that the present invention is not limited to the embodiment and various changes and modifications may be made to the invention without departing from the gist thereof.

For example, although the home game device generates the field image after generating the frame image in the above-described embodiment, the home game device may generate the frame image directly. That is, as shown in FIG. 1, in order to synthesize from the image data concerning line B, the im age data of line A and one of line B are necessary but any image data of other line is unnecessary. Therefore, it is possible to synthesize from the image data concerning line B instantly after generating the image data from line A to line C. Accordingly, it becomes unnecessary the memory capacity of the frame image memory unit 282 so that it is effective to a device under restriction about a memory capacity thereof.

Further, it was explained that the operation for correcting the lightness is carried on the synthetic result of Level 1, for example, in FIG. 3. However, the operation for correcting the lightness may be carried on the synthetic result of Level 2. An overflow and an underflow can occur due to the upper limit of each of RGB values (the 54 upper limit is "255" in the present embodiment) so that a position to be carried on the operation for correcting the lightness may be changed such an occasion demands.

Further, although in the embodiment of the present invention, it was explained by using the still image having rough pixels as shown in FIG. 2, it is needless to say that the present invention can apply to a moving image having more small pixels. The present invention has powerful to such the moving image specially.

Although it has been explained that all processing is carried on by S/W in the embodiment of the present,invention, one part of all processing may be dependent on H/W. That is, an apparatus for generating an image comprises a mechanism for carrying on any pixel interpolation processing generally. One processing may be processed at a higher speed by using the mechanism for carrying on the pixel interpolation processing.

More particularly, for example, it will be explained about the case that the apparatus comprises Bi-Linear Filtering circuit for sampling at four points as the pixel interpolation processing. As shown in FIG. 19A, when computing a color data of interpolation point X inside of four pixels of A, B, C, and D (or four texels may be used), the following operation is carried on at Bi-Linear circuit.

X=(l-a)x(l-p)x A + a x(l-p)x B + (1-a)x Px C + ax Px D A, B, C, and D represent color data of each pixel, respectively.

Herein, it becomes problematic that the color data of right and left pixels are synthesized by sampling at four points. That is, when applying the present invention it is necessary to synthesize from color data of only upper and lower pixels without synthesizing from color data of right and left pixels.

Therefore, after shifting the positions of pixels by 0.5 pixels horizontally the apparatus uses Bi-Linear Filtering circuit. That is, as shown in FIG. 19B, as a result of shifting the positions of pixels by 0.5 pixels horizontally, the pixels to be sampled by Bi-Linear Filtering circuit are changed to pixels A (100%), B (0%), C (100%), and D (0%). In this case, it is possible to synthesize from the color data of only upper and lower pixels without synthesizing from the color data of right and left pixels. Further, when synthesizing from the color data of pixels equally, the interpolation point X is in the center of four points to be sampled. Further, at step A5 of the line synthesis processing as shown in FIG. 16, it is possible to apply the color data synthesis processing for using Bi-Linear Filtering circuit for sampling at four 56 points.

Further, in case that the processing as well as one by Bi-Linear Filtering circuit has been realized as software, it is possible to apply as described above.

In the embodiment of the present invention, it has been explained that the image (color data) synthesis processing is carried on every "line" unit, for synthesizing from all pixels included in the next line after synthesizing from all pixels included in one line. However, it is unnecessary that the image synthesis processing is carried on every "line" unit.

That is, for example, as shown in FIG. 20A, the above-described image synthesis processing may be carried on the frame image in the vertical direction every a processing unit of 24 pixels by 16. Further, as shown in FIG. 20B, the above-described image synthesis processing may be carried on the frame image in the horizontal direction. Although the size of the processing unit is dependent on, for example, the H/W, the size thereof may be decided according to a capacity of cashing or paging.

The processing of the present invention is realized as a program (software) so that it is possible to extend an applicable field of the present invention easily by carrying on the processing as following.

57 That is, it may display a set up window wherein a user can select and change voluntarily whether carrying on the field image generation processing of the present invention or not or correcting the lightness to what extent. Further, it may generate the field image in obedience to the content on the set up window.

Further, it may automatically judge whether generating a field image according to the lightness of the whole frame image. In the case that the apparatus for executing the program (software) of the present invention is a game device, it may automatically judge whether generating a field image by the present invention according as whether a time is enough to generate a game screen of one frame (a frame image)..

According to the present invention, a main effect will be explained, as follows.

It is possible to lighten the lightness difference between the adjacent two lines on the screen of the display device and it is possible to reduce flicker effectively. Further, it is possible to realize the present invention by software so that, for example, it is not necessary to incorporate an exclusive field image generation device in a personal computer or a game device. Consequently, it is

58 possible to use a processor provided beforehand with the personal computer and the game device. Further, although the operation concerning image synthesis is restricted to using the result of operation at Level 1 at Level 2, it is possible to operate any data individually. Consequently, it is possible to operate any data at a high speed.

The entire disclosure of Japanese Patent Application No. Tokugan 2000219810 filed on July 19, 2000 including specification, claims, drawings and summary are incorporated herein by reference in its entirety.

59

Claims

What is claimed is:

1. A computer program comprising program code means for performing the step of:

synthesizing color data of an odd line and color data of an even line on a frame image at a predetermined ratio to generate a field image for an interlaced display.

2. A computer program comprising program code means for performing the step of:

synthesizing color.data of an objective line and color data of an adjacent line thereof on a frame image at a predetermined ratio to make a synthetic color data, to generate a field image for an interlaced display on a basis of the synthetic color data.

3. A computer program according to claim 2, further comprising program code means for performing the steps of:

synthesizing color data of the objective line and color data of an upper adjacent line thereof as the adjacent line on the frame image at a first predetermined ratio to make a first synthetic color data; synthesizing color data of the objective line and color data of a lower adjacent line thereof as the adjacent line on the frame image at a second predetermined ratio to make a second synthetic color data; and synthesizing the first synthetic color data and the second synthetic color data at a third predetermined ratio to make a synthetic color data, to generate a field image for an interlaced display on a basis of the synthetic color data.

4. A computer program according to any one of claims 1 to 3, wherein the predetermined ratio or at least one of the first, second, and third predetermined ratios is equal according to a number of objective lines of synthesis on the frame image.

5. A computer program according to any one of claims 1 to 4, further comprising program code means for performing the step of: synthesizing each color data per processing unit as a rectangular pixel group of a pixel number as a result of dividing a number of lengthwise pixels and a number of crosswise pixels on the frame image by a predetermined integral number respectively.

6. A computer program according to any one of claims 1 to 5, further comprising program code means for performing the step of: executing a translucent synthesis processing as synthesizing each color data.

61

7. A computer program according to any one of claims 1 to 5, further comprising program code means for performing the step of: executing a predetermined pixel interpolation processing as synthesizing each color data.

8. A computer program comprising program code means for performing: a first processing step of synthesizing color data of an objective line and color data of an upper adjacent line thereof on a frame image at an equal ratio by executing a predetermined pixel interpolation processing to make a first synthetic color data; and a second processing step of synthesizing color data of the objective line and color data of a lower adjacent line thereof on the frame image at an equal ratio by executing the predetermined pixel interpolation processing to make a second synthetic color data, and synthesizing the first synthetic color data and the second synthetic color data by executing a translucent synthesis processing to generate a field image for an interlaced display.

9. A computer program according to claim 8, further comprising program code means for performing the steps of:

62 executing Bi-Linear Filtering processing of sampling at four points as the predetermined pixel interpolation processing; and synthesizing color data of the objective line and color data of upper and lower adjacent lines thereof by executing Bi-Linear Filtering processing continuously after shifting positions of sampling by a half pixel horizontally at the first and second processing steps respectively.

10. A computer program according to claim 9, further comprising program code means for performing the step of: synthesizing color.data of a left or right end pixel on the objective line and color data of left or right end pixels of upper and lower adjacent lines thereof by executing BiLinear Filtering processing convolutedly, respectively.

11. A computer program according to any one of Claims 1 to 10, further comprising program code means for performing the step of: generating the field image as an image compressed the frame image in a lengthwise direction.

12. A computer program according to any one of claims 1 to 11, wherein the frame image comprises a size of 63 a screen of the interlaced display to display the field image or a bigger size than the screen.

13. A computer program according to any one of claims 1 to 12, further comprising program code means for performing the steps of: not synthesizing color data of an upper or lower end line and color data of another line on the frame image; or synthesizing color data of the upper or lower end line on the frame image convolutedly.

14. A computer program according to any one of claims 1 to 13, further comprising program code means for performing the step of: correcting color data of the field image brighter.

15. A computer program according to claim 14, further comprising program code means for performing the step of: changing a level for correcting a lightness of color data of the field image.

16. A computer program according to claim 14 or 15, further comprising program code means for performing the steps of: multiplying color data of the field image by a 64 predetermined coefficient to correct the lightness thereof; and correcting the lightness of color data of the field image after synthesizing color data of lines on the frame image when at least one of color data of the frame image exceeds a predetermined threshold value.

17. A computer program according to any one of claims 1 to 16, wherein the objective line of synthesis is different according as whether generating an odd field image or an even field image.

18. A computer program according to any one of claims 1 to 17, wherein the frame image is composed of full screen image data of theinterlaced display per time to display each field image.

19. A computer program according to any one of claims 1 to 18, further comprising program code means for performing the step of: changing ON/OFF of generation of the filed image.

20. A computer program embodied on a storage medium, the computer program comprising program code means for performing all the steps of any one of claims 1 to 19 when said computer program is run on a computer.

21. A computer program embodied on a transmission medium, the computer program comprising program code means for performing all the steps of any one of claims 1 to 19 when said computer program is run on a computer.

22. A computer program embodied in a carrier wave, the computer program comprising program code means for performing all the steps of any one of claims 1 to 19 when said computer program is run on a computer.

23. A computer program according to any one of claims 20 to 22, further comprising program code means, when said computer program is run on a home game device as the computer, the program code means performing the steps of: executing a predetermined game; and generating a game image of the predetermined game, composed of a field image reduced flicker.

24. A computer program according to claim 23, further comprising program code means for performing the step of: changing ONIOFF of generation of the game image composed of the field image reduced flicker, according to a progress of the predetermined game.

66

25. A computer program product comprising program code means stored on a computer readable medium for performing all the steps of the computer program according to any one of claims 1 to 19 when said computer program. product is run on a computer.

26. Apparatus substantially as described herein with reference to the 10 accompanying drawings.

26. A computer program product according to claim 25, further comprising program code means, when said computer program product is run on a home game device as the computer, the program code means performing the steps of: executing a predetermined game; and generating a game image of the predetermined game, composed of a field image reduced flicker.

27. A computer program product according to claim 26, further comprising program code means for performing the step of: changing ONIOFF of generation of the game.image composed of the field image reduced flicker, according to a progress of the predetermined game.

28. An image generation apparatus comprising program code means stored on a computer readable medium for performing all the steps 'of the computer program according 67 1 to any one of claims 1 to 19 when said image generation apparatus is run on a computer.

29. An image generation apparatus according to claim 28, further comprising program code means, when said image generation apparatus is run on a home game device as the computer, the program code means performing the steps of: executing a predetermined game program; and generating a game:mage of the predetermined game program, composed of a field image reduced flicker.

30. A computer system comprising a predetermined server and a predetermined terminal connected to each other through a predetermined electrical communication line, wherein the predetermined server comprises: program code means stored on a computer readable medium for performing all the steps of the computer program according to any one of claims 1 to 19 when said predetermined server is run on a computer; and means for sending said computer program to the predetermined terminal; and the predetermined terminal comprises: means for receiving said computer program from the predetermined server; and means for generating a field image reduced flicker by executing the computer program.

68 31. A computer system comprising a predetermined sever and a predetermined interlaced display device connected to each other t - hrough a predetermined electrical communication line, wherein the predetermined server comprises: program code means stored on a computer readable medium for performing all the steps of the computer program according to any one of claims 1 to 19 when said predetermined server is run on a computer; means for generating a field image reduced flicker by executing said computer program; and means for sending the field image to the predetermined interlaced display device; and the predetermined interlaced display device comprises: means for receiving the field image from the predetermined server; and means for displaying the filed image thereon.

32. An image generation method comprising all the steps of any one of claims 1 to 19.

69 Amended claims have been filed as follows 1 A method for generating field image data for an interlaced display, comprising the steps of.

synthesizing colour data from an objective line and an upper adjacent line in a frame image, at a first predetermined ratio, to make a first synthetic colour data line; synthesizing colour data from the objective line and a lower adjacent line in the frame image, at a second predetermined ratio, to make a second synthetic colour data line; and synthesizing colour data from the first and second synthetic colour data lines at a third predetermined ratio to generate a field image line for the interlaced display corresponding to the objective line.

2. The method of claim 1 wherein the first, second and third predetermined ratios are equal to one another.

3. The method of claim 2 wherein the first, second and third predetermined ratios are each 50%: 50%.

4. The method of any one of claims 1 to 3 further comprising the step of synthesizing each colour data in respect of a processing unit defined as a rectangular pixel group comprising a number of pixels.

5. The method of any one of claims 1 to 4 further comprising the step of executing a translucent synthesis processing method for synthesizing each colour data.

6. The method of any one of claims 1 to 4 further comprising the step of executing a predetermined pixel interpolation processing method for synthesizing each colour data.

7. The method of any one of claims 1 to 4 wherein said step of synthesizing said first and second synthetic colour data lines comprises executing a predetermined pixel interpolation processing method and wherein said step of synthesizing to generate said field image line comprises executing a translucent synthesis processing method to generate a field image for an interlaced display.

8. The method. of claim 7 further comprising the steps of.

executing bi-linear filtering processing of sampling at four points as the predetermined pixel interpolation processing method; and synthesizing colour data of the objective line and colour data of upper and lower adjacent lines thereof by executing bi-linear filtering processing continuously after shifting positions of sampling by a half pixel horizontally at the first and second synthesizing steps respectively.

9. The 'method. of claim 8 further comprising the step of synthesizing colour data for a left or right end pixel on the objective line and colour data for left or right end pixels of upper and lower adjacent lines thereto by executing bi-linear filtering processing convolutedly, respectively.

10. The method of any one of claims 1 to 9 further comprising the step of generating a field image line for display compressed in a lengthwise direction from the frame image.

-72,- 11. The method of any one of claims 1 to 10 wherein the frame image line for display has a length equal to or greater than a screen of the interlaced display.

12. The method of any one of claims 1 to 11 further comprising the step of repeating said synthesizing steps for each of a plurality of successive objective lines in a frame image.

13. The method of any one of claims 1 to 11 further comprising the steps o f:

repeating said synthesizing steps for each of a plurality of successive objective lines except for an upper or lower end line, and synthesizing colour data from the upper and lower end line of the frame image convolutedly.

14. The method of any one of claims 1 to 13 further comprising the step of correcting the synthesized field image to vary thefield image brightness.

15. The method of claim 14 further comprising the step of changing a level for correcting field image brightness.

16. The method of claim 14 or claim 15 further comprising the steps of.

multiplying colour data of the field image by a predetermined coefficient to correct the brightness thereof., and correcting the.brightness of colour data of the field image after synthesizing colour data of lines in the frame image when at least one of the synthesized colour data of the frame image exceeds a predetermined threshold value.

17. The method of any one of claims 1 to 16 wherein the objective line is different according to whether a field line being generated is an odd field line or an even field line.

18. The method of any one of claims 1 to 17 further including the steps of repeating said synthesizing steps for each of the plurality of objective lines in said interlaced display in a time to display each field image.

19. The method of any one of claims 1 to 18 further comprising the step of automatically switching on and off said synthesizing steps for generating the field image according to conditions prevailing in a processing unit.

20. The method of claim 19 in which the conditions prevailing include an assessment of the brightness of the whole frame image.

21. The method of claim 19 in which the conditions prevailing include an assessment of the time available to generate the frame image for display.

22. The method of any one of claims 1 to 21 performed on a game device, further including the'steps of. executing a predetermined game; and generating a game image of the predetermined game, composed of a field image having reduced flicker.

23. A computer program product, comprising a computer readable medium having thereon computer program code means adapted, when said program is loaded onto a computer, to make the computer execute the procedure of any one of claims 1 to 22.

24. A computer program, distributable by electronic data transmission, comprising computer program code means adapted, when said program is loaded onto a computer, to make the computer execute the procedure of any one of claims 1 to 22.

25. Apparatus specifically adapted to carry out the steps of any one of claims 1 to 22.